We tested exclusively with the Core i7 870 and the Core i5 750, the 860 didn't arrive in my lab until after the review went live. I was spending the greater part of a week with AMD at that time and didn't get to testing until this past weekend. Here's the chip:

What makes the Core i7 860 so interesting is that it's priced on par with everybody's favorite Nehalem: the Core i7 920. The 870 has great turbo modes, but it's nearly twice the price of the 860. The Core i5 750 wins in the price department, but it lacks Hyper Threading - part of what makes Nehalem so tasty in the first place. The 860 effectively gives us the best of both worlds, hence the focus on it for today's review.

I had a few mistakes in my original version of this table, but below you can see the turbo modes offered by the 860. They're not quite as nice as the 870, but the chip is also half as expensive. You'll also see that like the 750 you only get a single bin improvement with 3 or 4 cores active, but like the 870 you get 4 and 5 extra speed bins in the dual and single active core situations:

Max Speed

Stock

4 Cores Active

3 Cores Active

2 Cores Active

1 Core Active

Intel Core i7 870

2.93GHz

3.20GHz

3.20GHz

3.46GHz

3.60GHz

Intel Core i7 860

2.80GHz

2.93GHz

2.93GHz

3.33GHz

3.46GHz

Intel Core i5 750

2.66GHz

2.80GHz

2.80GHz

3.20GHz

3.20GHz

I've explained turbo mode in great detail here. In short, Lynnfield's PCU (Power Control Unit) looks at the number of cores active, shuts down those that are inactive, and uses the thermal savings to boost the clock speed of the active cores - all within the operating specs of the processor. Unless you're overclocking, turbo will never compromise system stability in search of greater performance.

Single Core

Dual Core

Quad Core

Hex Core

TDP

It works very well in practice, particularly with Windows 7. A question that's come up since the initial review is what happens when background tasks kick in. As I mentioned in the "Speed Limits" section of the Lynnfield review, this is something that can prevent turbo from kicking in:

"There's also the issue of background threads running in the OS. Although your foreground app may only use a single thread, there are usually dozens (if not hundreds) of active threads on your system at any time. Just a few of those being scheduled on sleeping cores will wake them up and limit your max turbo frequency (Windows 7 is allegedly better at not doing this)."

One of the features of Windows 7 is that the OS supposedly does a better job of grouping tasks together on a single core to avoid waking up an adjacent core and negating the gains from turbo mode. I'm still working on finding a good way to measure this but from what I've seen initially, Windows 7 tends to do a good job of grouping threads onto one or two cores - meaning we tend to see the 4-bin or 5-bin turbo modes. The other thing to keep in mind is that the processor can turbo up/down faster than the OS can schedule threads, the benefits of turbo are present even while in the middle of executing a task. Remember what dictates turbo is both thermal dissipation and current consumption; the mix of instructions executed varies depending on the task and even during the task, which in turn varies the frequency your core(s) will run at.

The end result is a system that seems to feel more responsive as well as perform better. Of course none of this matters if you're going to be disabling turbo and just overclocking, but I've addressed that scenario in a separate article today :)

And I don't really have a reason for showing this, but I like tables so here's the current quad-core processor landscape:

the story is even worst than that:
somewhere at satan clara's intel's HQ the evil orcs at intel decided that free overclocking was not profitable so they decided to create the turbo crap story, and call it a 'feature' so this way they would use all available overclocking headroom in the cpu and begin charging for it.
so they are killing free overclocking for intel users.
now you have to pay for overclocking because lynnfield turbo overclocking is consuming all the overclocking ability of the cpu
now intel can make this turbo overclocking more aggressive in some cpus and charge more for it.

but there is another problem because intel's orcs betrayed the evil nvidia warlock who sweared revenge and now intel cpus are underperforming when paired with an nvida graphics card.
Reply

Not really... Just look at the numbers. The i5 750 is outperforming the PII 965 in almost every case. And when the 965 pulls ahead, it's not enough to justify the increase in price and huge increase in power draw. Reply

> Not really... Just look at the numbers. The i5 750 is outperforming the PII 965 in almost every case
... when given room to Turbo. When not given room to Turbo, then the winner is...? Based on the limited number of Turbo off benchmarks available, my theory is that the i5 750 will fall below the 965 with no room to Turbo. I'm not completely convinced yet that the i5 750 is the definitive winner over the 965. CPU comparison's aren't that clearcut anymore with the variableness of Turbo mode.

On a side note, I do agree the price tag of the 965 is certainly too high, even if the 965 is hypothetically better than the 750 under heavy load. Maybe AMD is fighting the 750 with the slightly lower priced PII 955, which anyone can multiplier bump into a 965. Reply